Nowadays, large amounts of waste paper are discarded from offices, publication houses, paper manufacturing companies and the like. In general, at a stage during manufacturing of paper from wood, paper receives a high degree of processing in order to render cellulose fibers finely softened, such that paper is a functional material having a value-added structure. Therefore, waste paper is also a functional material having a value-added structure. Moreover, waste paper is a material that is effectively zero in terms of its environmental impact. Consequently, proposals have been made for using resin compositions containing paper, in which pulverized waste paper is mixed, for molding process materials.
For example, in Patent Document 1, a resin composition containing paper is disclosed in which a composite paper having a polyethylene resin on one or both surfaces thereof is shredded in a small piece state, a granular state, or a powdered state of about 1 mm to 5 mm square by a chopper or pulverizer type of shredder or the like, and such shredded paper components are mixed at 50% by weight or greater with a synthetic resin component of polyethylene or the like.
In Patent Document 2, a resin composition containing paper is disclosed in which collected waste paper, such as laminated paper or the like from liquid containers, is crushed to a particle diameter of 0.5 mm to 2.5 mm, and the crushed paper is mixed at not less than 51% by mass with a polyethylene or polypropylene resin.
In Patent Document 3, a resin composition containing paper for use in molding processes is disclosed, which contains in excess of 50% by weight and at or below 70% by weight of a low combustion component in powder form consisting mainly of paper powder and having a particle size of 50 μm or greater and 200 μm or less made by grinding waste paper or the like, and 30% or more by weight and less than 50% by weight of a high combustion component made up mainly from a thermoplastic resin.